I noticed on my 03 that i've had since January that alot of the time if i engage the A/C there is a noticeable thunk from the right side of the truck. Like someone smacks my tire with a hammer. But since it seems to work i havent really worried about it.

I did notice that in a RC truck with only 45k on it i thought the a/c would blow colder. I tried it on both modes.. and actually it seemed like the normal outside-in mode was cooler. But overall only felt like about 50-60deg air coming from the vents.
I hate to go messing with refilling it myself as i recently blew the pop-off on my g/f's Jeep compressor doing this. But if this works on our trucks i'd try it once.

Thanks for the help